Check your wire connections at the coil and also the pickup lead from the distributor. Sometimes that plastic connector will melt from its proximity to the exhaust manifold. Also check your coil wire. They can go bad or just be loose. I doubt it’s the igniter. They’ve all electronic. Either they work or they don’t.

 

Hey Fred, you left out the coil wire.
Igniters can cause silly misses as they slowly die. Sometimes they just die, sometimes they drop out as they warm up and then come back as they cool. Typically the capacitors dry out or leak causing erratic performance or failure. Gives the on and off thing. The connector or a ground could be the problem though.


Either way, hope he gets it back soon.

 

Sounds like temp has a factor in it shutting off.. does it start right back up or does it hesitate?

 

In an issue with the igniter temp IS an issue, externl temps and internal. When a cap goes bad it can act like an open or a short, or even both at the same time. Weird little component. A cap on it's way out could cause an intermittent misfire or even a searching type misfire. The pickup coils in the distributor can be affected by heat as well if they're going out. If it were an issue with vapor lock starting would be hard after shutting down, but not a rough running issue.

Just my 3 cents.

 

I’m going for igniter as the issue too. One on a 20R Celica i work on was coming and going. Would always start again at some point. Then recently it finally fell on it’s face and stayed down. Narrowed it down with a multimeter to the igniter. Finding one was rough, not looking forward to when this replacement one goes. But it’s purring real nice again now.

 

Want to test the igniter? Warm it up to the point where it starts causing porblems and then ice it. If the issues go away after cooling..... Igniter.